A conventional way of measuring an acoustic wave's time-of-flight through a material employs a “pitch-catch” system. Briefly, an acoustic pitch-catch system introduces an acoustic wave (e.g., an ultrasonic wave) into one side of a material and then detects the acoustic wave as it exits another side of the material. The time to transit the material may be used to determine various material characteristics such as the material's velocity characteristics, which are useful in calculating a material's elastic moduli. Typical pitch-catch systems utilize multiple transits of the acoustic wave (i.e., back and forth through the material) in order to minimize the effects of the time delay between the system's “electric zero” and “acoustic zero.”
A system's electric zero is defined as the start time of the energy pulse used to generate the acoustic wave at the system's transmission transducer. However, system “electronics” (i.e., to include the energy pulse generator, wiring coupling the generator to the transmission transducer, and the transmission transducer itself) introduce a time delay such that the time that the acoustic wave is actually introduced into the material (i.e., the acoustic zero) is delayed relative to the time of the electric zero. The above-mentioned multiple transit approach is relatively effective when the material supports multiple transits of the acoustic wave as the effect of the time delay is spread out over the multiple transits. However, if the material under test is highly attenuating such that multiple transits of an acoustic wave are not supported, the error introduced by the time delay between a pitch-catch system's electric zero and acoustic zero can be significant.